I concur that 18x9 ET31 255/35r18 will most likely require camber. I'm 18x9 ET41 (soon to be ET38 or ET36) 255/35r18 Toyo Proxes R888 (tire sizes vary!) and I'm really close on the outside with pins...

Yeah, what I figured too, but I didn't press the issue because they're cool. I'm FBO/JB4 ISO/race backend flash and the only thing I do when going in for warranty/service work is put the JB4 on map0...